In medicine, a syringe is usually used for blood sample collection or drug injections.
Referring to FIG. 1, a conventional syringe 10 comprises a barrel 11, a plunger 12, a needle seat 131, a needle 133, and a tip protector 14. A rubber ring 121 is disposed at one end of the plunger 12. The plunger 12 can be placed into the barrel 11 from the second opening 112 of the barrel 11. The needle 133 is fixed in one end of the needle seat 131. The other end of the needle seat 131 is connected to the first opening 111 of the barrel 11. By pulling or pushing the plunger 12, a liquid can be drawn into the barrel 11 or pushed out of the barrel 11. The collection of blood samples and injection of drugs can be achieved by using the syringe 10. After using the syringe 10, the needle 133 and the needle seat 131 are sheathed in the tip protector 14 for safety.